Mod Chrisso says it's ok, nothing to worry about. Apparently a bit of the code had slipped through to the website, and they were gonna remove it or have removed it now.
Even clicking accept on it was apparently according to him totally harmless.
This is actually nothing to worry about. We accidentally duplicated a little snippet of code from another of our pages and misplaced it here - whether you allow or deny, you'll be just fine. It's code we already use on another page to check whether you have Java installed, so that you don't get a blank page when you click Play Now and have a bad Java version.
Edit: We're getting the code out so it should disappear when we next give the forum a kick (relaunch it).